Massive oil spills such as the Exxon Valdez incident in Prudohe Bay, Ak. and the Deepwater Horizon incident near the central Gulf of Mexico coast are well known environmental disasters. These and other similar events cause long-lasting damage to coastal wetlands and beaches by fouling wildlife and destroying their habitat. The intrusion of pollutants carried by tides and currents into the shallow marshes kills vital vegetation needed to withstand erosion and loss of wetlands. Further, the fouling of beaches severely impacts property values, is expensive to remediate, and causes serious economic harm to beach communities.
When a spill or discharge occurs in or near a body of water, containment booms are often deployed in an attempt to prevent the pollutants from reaching sensitive areas. In addition, absorbent booms are sometimes also used in conjunction with the containment booms to remove the pollutants.
Both of these types of prior art booms have similar characteristics in that they are generally constructed of many individual segments assembled together into long strings that constitute an extended floating boom. The interconnections between segments provide for significant flexibility so that the boom elements can freely orient at various angles with respect to each other. Thus the overall shape of the deployed boom is flexible and dynamic as the individual elements are subject to winds, currents, and wave action. Generally, such booms are towed from one end of the string to a desired deployment location. Each end of the boom is then connected to a submerged boat-type anchor to fix its location. In practice, it is often difficult to properly deploy such booms, particularly when they are made up of many elements and the winds and currents are strong and opposing, and/or the seas are rough. Further, it is impractical to employ such containment booms in very shallow waters such as wetlands where navigation of powered vessels or other access is restricted.
In addition to the deployment problems, these prior art containment boom systems are unreliable in practice. Rough, choppy waters and waves allow pollutants to overtop the floating barriers and thus reach environmentally sensitive areas. In addition, such conditions, including strong winds, often cause the anchors to slip with the result that the desired protective posture of the boom is compromised. In many cases, such booms have been observed to actually wash up onto the beaches or shoreline they are intended to protect and are thus rendered useless.
Most barrier booms are constructed of a dense nylon fabric with a longitudinal pocket at the top that encloses flotation material. A length of cable is also sewn into the barrier element at the very top, above the flotation material. Below the flotation pocket the fabric forms a skirt that extends down a few feet below the water surface. At the very bottom of the skirt is a fabric channel that houses a length of chain that causes the skirt to drag below the surface. There are coupling means at each end to allow individual segments to be assembled into long boom lines. Barrier booms are inherently expensive since their manufacture requires several types of materials and multiple manufacturing steps.
Absorbent booms are much simpler in construction. Basically they consist of long “socks” of porous nylon tubing that are filled with absorbent material. Attachment elements are sewn in at both closed ends of the sock, allowing them to be strung together in long boom lines. They are designed to float on the surface of the water and thus capture pollutants there such as hydrocarbons.
Other methods of protecting wetlands and beaches from harmful pollutants involve the use of bales of natural materials such as hay or straw materials strategically located at the waterline immediately adjacent to the wetland or beach areas to be protected. Depending on the tides and waves, the bales are partially submerged while resting on the shallow sea floor. The particular benefit of these methods is that the bales are deployed so as to provide a protective barrier while simultaneously providing an absorbing medium to capture any pollutants that encroach on their location.
One of the drawbacks of the prior art methods involving the use of bales of natural materials is that they are usually deployed individually and great care must be exercised to avoid gaps between the neighboring bale elements, otherwise the deployment will fail to provide a seamless barrier. Even when successfully deployed without gaps it is harder to prevent gaps from developing after exposure to winds and wave action as the individual bales may break apart and be displaced from their initial position.